for the sake of an angel
by owedbetter
Summary: One night, the sky disappeared. [zutara au for zutara month, day 6: constellations. one shot.]


" _One may tolerate a world of demons for the sake of an angel._ "

Marquise de Pompadour, _The Girl in the Fireplace_ (Doctor Who)

* * *

One night, the sky disappeared.

At first, the Fire Nation supremacists rejoiced for the sudden darkness had come at _night_. Foolishly, they did not yet know what it would mean for total darkness to swallow up the skies. Clearly, the spirits had seen them all to be worthy of their favour. Fools, the lot of them. Admiral Zhao, at first, claimed that it was he who was cause for their joy for he'd _succeeded_ in taking over the Northern Water Tribe and it was he who had vanquished the spirits of the Moon and the Sea; Tui and La were no more, according to him.

But, as his uncle often said, there needed to be balance in the world.

The Banished Prince scoffed as he looked out at the window.

Zuko believed only in what he could see. Right then, as he looked up at what used to be the sky, he could see absolutely nothing.

Come a few hours later of what might have been the morning or the afternoon, chaos ensued. By then, the entire world cursed the name of Admiral Zhao and the Fire Nation for the great injustice that was brought upon them by this supposed killing of the spirits. Because it was not only the moon that had vanished from the skies – it was everything else too.

The stars were gone, and gone were the very constellations that guided any seafarer anywhere. The sun did not rise. No clouds drifted above them. And, lastly, there was absolutely no wind that blew.

He awoke to his ship crashing into tumultuous rock formations by the shore that no one had seen. His crew were yelling into the infinite darkness as they were tinged with rotating red lights. Zuko woke drenched in sweat, breathing hard and with great difficulty; the air around him was thick with smog. It was like swallowing poison and letting death into your body but the alternative was still just another form of death. He heard splashes come from either ends of the ship as men and women threw themselves overboard and into the coolness of the water; some bodies landed in matter that was not quite as forgiving.

What light they all had was manmade – from the red of the emergency lights of the ship, to the flickering orange from the torches.

To most, the former Crown Prince was a skeptic. He believed in only a few things – in the wisdom and righteousness of his uncle, in justice, in truth, and in honour. But this… this felt too divine an intervention that, for a moment, he felt his heart beat in tune to a begging hymn older than him, a song that will outlive him 'til the end of time, and his heart was crying out to anything out there higher than him that was listening. _Save us_ , it beat.

 _Save us. Save us. Save us._

Still, he was not about to become a believer in the blink of an eye and he moved with purpose. The memory of his muscles was still sharp. He'd been on this damned ship enough times to know his way and he gathered what he could and he blindly moved about the chaotic ship, looking for his uncle. He had reached the deck, yelling for his uncle, when he felt the ship start to shake once again as the damage done by the rocks was more pronounced. The sea poured uninvited through the cracks. Most of the torches had fallen into the water at that point.

His uncle was the last thing he could remember thinking about above water and he screamed it – " _Uncle!_ " he'd called out – into the uncaring darkness before his body met with the sea. When he was welcomed into the embrace of the watery abyss, his lungs burning with the acrid smoke-filled air that was all he could breathe, he could have sworn that he heard an _unearthly_ sound.

A wheezing, groaning sound.

Zuko did not believe in much but as his eyes started to give in to the weight, he saw a light from the depths of the ocean floor – and what looked to be the outline of a big, blue box. Impossible, yes, but right then as he felt the air pass from his lips and as he drifted towards the bedrock of the ocean floor… he could afford to believe in a little bit of the impossible.

* * *

"Oh good, you're awake," he heard her say as he stirred into sitting up on the soft chair he had apparently fallen asleep on. Zuko groaned.

"Wh—" he started, the inside of his wrist rubbing his eye as his fingers brushed and scratched at his scalp. "W—where's Uncle?"

"Aww, that's nice. I just saved your life and you're in an alien spaceship but you're worried about your _uncle_ ," said the strange woman – who seemed to only get stranger by the second. "Not that I'm complaining. Don't get me wrong. It's cute."

" _What?_ " he asked, barely registering what she was saying for she spoke at a speed that was probably faster than lightning. He blinked, his mouth hanging open. Dumbfounded. Finally, he asked, "Who _are_ you?"

"First things first," she said as she took something out of her coat pocket. A blue stick that glowed at the end – and it whizzed in her hand. His golden eyes widened at the thought and his arms fell to his sides, stiff, and he held on to the sides of the plush, leather-like chair. He watched the light as it scanned him. The woman twisted the device back to her, flicked a switch on it, and clicked it again, but the light glowed white that time. "Tiny bit of oxygen deprivation. No real surprise there. Nothing a few nanobots can't fix."

She pointed the glowing stick at the chair and, suddenly, a flurry of little blue lights surrounded his entire form.

" _What?_ " he asked, loudly. He practically jumped up to his feet but slumped back into the chair just as quickly, for his lungs had complained for the effort. He swallowed and watched the light glow around him, a faint blue around him. "What is that? What are you doing to me?"

"This?" she said, pointing to what looked to be her magic glowing stick. "It's a sonic screwdriver. And those lights around you are nanobots; they're restoring you to factory settings, to be a little crude. Sorry about that. Just fixing you up quicker than regular medicine and rest, would. Can't do it all the time, though. That would really mess up your insides."

"My _what?_ " he said, even louder this time.

"Easy," she said as she went back to the controls.

It was then – and only then – that he had noticed his surroundings. If he thought that the woman, the glowing stick, and the little healing, glowing lights were strange… it was nothing to say of this… insanity that he was apparently trapped inside.

The room was expansive – a favoured blue scheme dominated the entire room. The middle of it was a pillar-like structure with little tables that stretched along it that filled with blinking lights and levers and toggles and switches and other controls that boggled the banished prince's mind. A console. The walls her covered in what looked like icicles, but sleeker and smoother and colder. The floor was nearly translucent, like he was sat atop thin ice and instead of freezing ocean beneath it, there were more wires and little lights that blinked intermittently. There was a staircase to his side and a hexagon-shaped door that led to a hallway, that led to… somewhere he did not know. And did not care to know.

It was too strange that he thought that must have been a dream.

But, then again, he was never quite so imaginative (nor was he as narcissistic) to ever think that he could be capable of making something like _this_ up. Zuko stared at the space before him with his jaw hanging; he'd even forgotten about the little glowing lights that surrounded him. The woman pointed her glowing stick that she'd called her sonic screwdriver at him again, and the lights flew past him like little constellations, back into their little pocket of hidden space – somewhere he could not see.

His breath and racing heartbeat were caught in his throat.

"What _are_ you?" he managed to ask in a disbelieving whisper.

"Oooh, a _what_ are you. That's different. Little rude," said the woman.

"Are you a—" He gulped. "A spirit?"

"No," she said, smiling.

"A… _god?_ " he asked.

"Nah," she answered, grinning that time. "Too much responsibility. And sure, I like to be thanked _sometimes_ but worship's a bit much."

Possible higher being or not, Zuko rolled his eyes and scoffed.

"Are you going to give me a straight answer?" he dared.

"Probably not," she told him. "But just so you know… I'm the Doctor."

She said that as if it was all the answer he needed when, in reality, it only gave him even more questions.

The woman called the Doctor, he noted, had the bluest of any blue eyes he had ever seen in his life. Bright and wide, she looked at him with a curiosity he could not quite place. There was a fierceness about her – a fire in her bones, in the dust of her atoms – that made his heart race in anticipation, in fear, and in excitement. As if everything about his system and his training told him that there was danger in her presence – and yet instead of running from her, he wanted to gravitate towards her.

Her skin was dark and smooth against the bright, pale blue lights of this… _place_. Her hair was long and dark – all wild curls, like the waves of the ocean – with two hair loops that started from her forehead, bound by two small blue beads.

She had on what looked to be a light blue coat with a trim of bright white fur. Beneath her coat was another blue shirt that was loosely fitted – cinched at the waist by what looked like a leather, rope-like belt – and beneath the shirt were loose trousers, the darkest blue of her entire getup. Her entire outfit was blue, really, save for her suede brown boots. And he'd thought he had a dedication to an aesthetic – with his primarily red wardrobe.

She was impossible, he decided. This wild, madwoman who had apparently saved his life. All he could remember before waking up to this strange, dreamlike reality was slowly drifting to the ocean floor and now he was here. Perhaps he had died in that life and this was simply him awakening in another.

Was that how existence worked? Was it just simply waking up with no recollection of how you got there – nothing except the memories in your mind, without your clear recollection of how you'd gotten those stories in your head in the first place? Zuko didn't know. Zuko didn't care to know – this was not the time, this was not the place to contemplate his place in the universe.

The Doctor leaned against her console and looked at him, amusement dancing in her eyes.

When you have eliminated the impossible, whatever remains, however improbable, must be the truth.

"You're a doctor," he said, finally.

"Sort of," she said, shrugging her shoulders as she crossed her arms against her chest.

"But you _just_ said—"

"I said I'm _The_ Doctor. Not _a_ doctor," she said cutting him off and raising a hand up. "Big difference. And I never really paid attention to those bits at The Academy. Yugoda was a bit of a bore and Pakku was _way_ too up himself. Still, graduated so I know _some_ things about it, sure. But still, I'm the Doctor."

Zuko blinked up at her – not entirely willing to subject himself to the argument that nothing of what she'd said to him made any sense to him whatsoever.

"Where _am_ I?" he asked instead.

"She's called the _TARDIS,_ " the Doctor answered. "Time And Relative Dimensions In Space. Really, she's more like a Time Capsule but my granddaughter thought up a new name for her a few thousand years back. And she's my _ship_. You're on my ship, to answer a long story short. Any more questions?"

"—granddaughter?" he asked again, voice raised. "You can't be any older than I am!"

She winked. "Speaking of you, what do _I_ call _you?_ "

"Me?" he asked, taken aback. "I—I'm Zuko—but hold up. Wait. Nothing about this makes sense."

"Maybe not to you," she said. "To me, it's Tuesday."

"But who _are_ you?" he pressed again, unwilling to give up without a fight.

"I've told you," she said more seriously this time – perhaps he was not the only one who was losing patience. "I'm the Doctor."

"No, that's not a real name," he argued. "Who _are_ you?"

" _Who am I?_ " she said, fire in her voice now too. There was a sense of command there and something in his blood sang to him to succumb, to yield to her orders. She approached him, face getting closer and closer to his as she spoke with an ominous tone. "Right now, I'm the one chance you've got at staying alive and saving your planet so _just do as I say._ You get all that?"

He did not know what powers this woman had over him. Logically, there was no reason for it. By the look of her, she was roughly the same age as him. Despite her nonsense, there was something about the way she spoke that made him listen. There was something in her walk that made him follow. There was something in her truth – no matter how ludicrous it may have sounded – that made him believe her.

There was no rationality to it; was this what _faith_ felt like?

Her stern look melted away when he swallowed and said nothing to her statement, which he supposed she had taken as his agreement. The Doctor's smile returned to her dark lips and she twirled and turned to the console of the TARDIS. A large, glowing light at the very middle of the console started going up and down as she operated the console. Then came the wheezing, groaning that he had heard before. She started pushing buttons and toggling toggles and lifting levers in ways that made Zuko's head spin and yet, still, he followed her around and asked.

"Are you going to tell me what's happening?"

"Doubt it'd make sense to your tiny little brain," she said, unfazed and still solely dedicated to the movement of operating as many of the console's controls as possible. He felt the ground beneath them shake. She continued, "I mean… no offense. All humans are like that."

"But _you're_ human…" he argued.

"Want to bet?" she asked, grinning again.

"You can't be _not_ human—look at you!"

With two hands on switches that she switched to a position, she swiftly turned to him – which caught him by surprise. She took one of his hands and pressed the back of it against her chest. His gold eyes widened and he swallowed as he felt a rush of warmth rise suddenly to his cheeks. But, just as soon as it appeared, his embarrassment was replaced with even more confusion.

How that was even possible, he didn't know.

Yet, there was the unmistakable vibration he felt in her chest. The beating too fast, too erratic to be normal. This woman… the Doctor had two hearts. Zuko looked squarely at her chest for a moment, focus solely on the foreign twin heartbeat he felt against the back of his hand, and when he looked back up into her blue eyes, there was a mischief in them that he could not place.

Just before he spoke to ask, she released his hand and pulled down a lever from the part of the console next to them. The moving light dimmed and halted. The wheezing, groaning sound stopped. The floor beneath them stilled completely.

He licked his lips and looked around as the lights started to dim.

"And if you're _really_ not sure…" she said, quiet but a small smirk curled on the side of her lips. "Check outside."

He turned to look at the closed doors that looked like they were made of wood and painted white on the inside. She snapped her fingers and they were pushed in.

More and more, he felt like he was losing his mind. For beyond those doors, he could see the darkness of the ocean, barely lit by the inside of the TARDIS. He walked, his footsteps slow and uncertain, towards the door.

"We're at the bottom of the ocean!" he exclaimed, pointing at the ocean and looking at her with his eyes as blown as they could be.

"Sure about that?" she asked. The Doctor snapped her fingers again and the doors closed shut.

She went about her dance around the console, switching and flipping and turning and twisting and toggling and pushing and pulling things before he could even make sense of any kind of routine. She moved like a natural disaster – unpredictable and chaotic – and yet she flowed with the grace of gravity. Every push and pull of her had purpose. Zuko only followed and watched, silent and afraid and beyond manically thrilled for some reason unbeknownst to him. Before he could notice it, his lips were starting to quirk up into a kind of smile.

When the wheezing and groaning of the TARDIS, he swiftly turned to the doors again. The Doctor smiled and snapped her fingers, opening the doors. Out the doors, there was the darkness of night but where had only seen nothing before… there were now stars.

So, so many stars.

More than just stars, even. A field of constellations made of other planets, other galaxies, other universes just spread out before him for there were more of everything that had ever been. There was so much more than he had ever imagined were possible.

He peered his head out of the box to get a closer look. The Doctor nudged him for she had stepped to stand right next to him.

"I—" he started to say but could not find the words. There were not any – language was far too barbaric a concept to wrap its concept around the majesty of this sight.

"Yeah," she said. "It gets me every time too."

"No way," he said. "What _are_ you? What is this?"

"Everything," she said, shrugging her shoulders. Her small smile turned into a grin as she pushed him out of the TARDIS entirely and he felt his entire body give way. Zuko screamed into the abyss while she laughed, leaning against the doorframe and watching him struggle to swim on space.

He floated in the pocket of air that surrounded the ship and he was now part of that nothing he'd thought he'd seen earlier. That pocket of space that he'd thought was so dark before turned out to be covered in stars, in space, in light and life. He smiled. And as he drifted further and further away, he turned his head and saw the Doctor still standing there and watching up at him, but he'd noticed that the TARDIS was barely just… a blue box. Two people couldn't fit in that thing – let alone a room as big and as expansive as the one he'd just been in.

Sweet Agni, nothing about this made sense. Yet, instead of dread, he'd found himself set alight. There was so much to be known – and so much she'd shown him in such a short amount of time. Zuko swam back to the door, where she reached out to grab him by the arm and pulled him back down to the TARDIS' gravity.

"How does it do that?" he asked once he regained his breath, stepping back into the ship. The Doctor followed him in. "How is it so much bigger on the inside?"

"That she is," she said. "Don't you love her?"

He raised a scarred brow bone at her, his bones still buzzing with questions yet not knowing how or where to start. But the Doctor gave him a pointed look and said, "Right now, I'm transmitting an atmospheric converter to the entirety of your planet for oxygen redistribution. Don't know who's encased an entire planet into a hard-cased Anino Bubble but that's what I'm here to find out." A pause as she looked to the air, mouth open, as she reconsidered that statement, and then she said, "Actually, I was here to look for people who could command their planet's elements. And a sort of… _Avatar_ who could command all of them."

"You mean _benders?_ " he asked. "There haven't been any benders in a thousand years. Besides, even if you believe all of that, the Avatar's just a legend."

"I take it you don't?" she asked him. " _Believe?_ "

"They're only stories," he said. Instinct, despite everything he had just seen.

"Haven't you learned anything from me yet, Zuko?" she asked. "The stories are almost always true."

The Doctor smiled.

"Now, let's go save your planet."

* * *

 _She was like fire and ice and rage._

 _She was like the night – and the storm in the heart of the sun._

 _She was ancient and forever._

 _She burnt at the centre of time and space and she could see the turn of the universe._

 _And she was… she was_ wonderful.

* * *

When the day was saved and the aliens that had tried to ransom Zuko's Earth were defeated, he found the blue box sitting by the beach, overlooking the stars that had been returned to their night sky – as well as the fullest full moon that had never quite looked so big before.

Zuko did not know how one woman could save a whole planet, could restore him back to his birthright on the line of succession, could bring him back from the brink of death, could save his uncle – all on her own. Yet, no one ever knew her name. No one would remember her except him, because he'd known her. And she'd disappeared from the narrative too quickly for anyone to truly understand what it was that she had done and what it was that this Doctor was capable of.

"I still don't believe half of the things you say your ship can do, you know," he said to her as he sat down on the sand next to her. She didn't turn to him as she kept her blue eyes upon the moon – skyward, to the stars.

Home to her, for she'd come from the moon and stars herself.

"I could make you believe," she said, a small smile playing on her lips. Still, she did not look at him.

"How would you do that?"

"Well, for a start…" she said. "You could come with me."

"Come where?" he asked.

"Come with me," she offered, finally sparing a look at him – one so tender, so hopeful that it was difficult to believe anyone could say no to her. "See the universe. Travel. Have adventures."

"You're _asking_ me to go with you? In that blue police box?"

"I'm not asking. Don't get too full of yourself," she said, nudging him with her elbow. "But if you want to come along… I wouldn't say no." The Doctor bent her head and looked down at the sand, her fingers brushing against the coarseness of the fine, fine earth. She added, "It's been a while since I've had someone else along with me."

"You mean… other people have traveled with you?"

"A few."

"Where are they?" he asked. "What happened to them?"

"You know how it was today?" she asked. He nodded. It was mad and beautiful and insane and incredible and frightening and invigorating and… more than he could say. He licked his lips. "It's kind of always like that with me – sometimes better, sometimes worse. So, a few of my… _companions_ , they… they _leave._ Sometimes, because they should. Or they find someone else. Some of them forget me. Depends, really," said the Doctor.

She looked to the sea and sighed. "I suppose in the end… they break my hearts."

"So, why should I go with you?" Zuko asked. "If I'm just going to break your hearts?"

"Maybe I'm hoping you'd be the one who won't," she answered. "It's not my job to convince you, Zuko. I'm _above_ begging. Please. I'm a Time Lady—I'm beyond that." She sighed and rose to her feet. The Doctor didn't even bother brushing the sand off of her clothes. She just started walking towards the outline of her box. He hadn't even had the chance to start to get up too.

"Anyway, I can see you've made up your mind about all of this," she said, a hand against the wood of her magical ship.

"I—" he started. "My uncle—"

"It was nice to meet you, Prince Zuko," she said. "Take care."

And just like that, she was back inside the box. Before he knew it, it started to dematerialise right in front of his eyes. The wheezing, groaning sound came back and he could not find the words to describe what it felt like to leave and lose her at the same time, before he'd even had the chance to think about what it was that he was giving up in the first place.

But, before he could even admonish himself for not getting to say goodbye to her properly, the box started to materialise in front of him again and that wheezing, groaning sound returned. He blinked at the sight, jaw hanging, as the Doctor popped her head out after she opened a single door.

"Did I mention it also travels in time?" she asked.

His jaw dropped even lower. She raised a hopeful brow.

"Is that supposed to convince me?" he said, starting to smile..

"Well, I could drop you off back here and not five minutes will have gone, so…"

"That's impossible," he said, grinning now. "You can't travel in time."

"But I _can_."

"Prove it."

"Come with me."

"…Five minutes?"

"Cross my hearts."

* * *

Zuko did not believe in a lot of things.

He mistrusted the existence of luck. He'd always gotten by on his own, after all, and it made him strong. He refused the idea that anything or anyone else was in charge of his destiny. He had chosen his own path long ago and he was the author of his story. No matter the tales of the faithful and their clinging to the practises of spirits or gods and devils. He refused to be the victim – and he wasn't.

He won't be.

But, in this big blue box of impossible things, he's seen more of this universe than anything else he could have dreamed of. There was so much of time and space that he did not understand that, perhaps, one might not have blamed him for a shift in faith. He might find salvation or prayer lingering in his heart; he might believe in fairytales, now that he was in one.

But he didn't, he told himself with particular conviction. He didn't.

There will always be fake gods and bad gods and demigods and would-be-gods. The whole pantheon of the cosmos could reveal itself to him and still, he would not be shaken. Science and reason and logic and honour still ruled above all else.

But in that moment, looking at this incredible creature before him as she danced around the console and started prattling on about an entire planet made of ice, he knew it in his heart that if he could only ever now believe in one thing?

Just one thing?

He believed in _her_.


End file.
